As computer users become increasingly sophisticated, there is an increasing desire for efficiency in the computer programs that people use. For example, many computer systems have some type of file management system that manages hundreds, or even thousands, of files, to which a user may need access. In many traditional file management systems, it is difficult to ascertain the contents of a particular file without actually opening the file, using the necessary application associated with the file type for the file. Oftentimes, the only useful information that the user can obtain about a file before opening it is the file name. Many users would like to be able to preview the contents of a file before actually committing resources to opening the full application and then the file. Some file management systems, such as the Finder in Mac OS X, offered by Apple Inc. of Cupertino, Calif., provides functionality for previewing files before opening them. Other operating systems and file management systems may also offer some static previewing functionality.
For example, using Apple's Finder, a user can preview documents, such a PDFs, text files, word processing documents, and spreadsheets, etc. Finder also allows a user to preview certain video content that has a native file type recognized by the Mac OS.
The Quick Look daemon in the Mac OS incorporates a variety of plug-ins, each of which accepts a particular data type from a client process and converts it into a preview in one of a set of standard format, such as PDF and HTML. The standard format previews are then displayed by the client process using the Quick Look framework. The advantage of this structure is that it avoids a client application crash being caused by a third party plug-in crashing. However, this model does not work particularly well for dynamic media, such as streaming media, because converting dynamic media associated with a non-native filetype into a suitable standard format, takes too much processing time to be useful or reliable.